I've had a lot of people comment on my new skins and ask how I made them so well, so I figured I would throw together an index of helpful tips on making your skins look their best.

Edit July 24, 2011: I am adding this at the top because it's something I find myself pointing out countless times lately:
0. DO NOT PREVIEW YOUR SKINS ON A MUSE/RUMP SHAPE. They're cute shapes, yes. However they are absolutely HORRIBLE to use for making skins. The reason for this is because the stomach on both(Rump is the booty version of Muse) is very warped on these shapes and it distorts the skin completely. What may look great on the Muse shape may look totally weird and ugly on a normal shape. Muse pushes the navel downward and changes the entire look of the stomach. For example, the screen shots below show the differences between my Mirai shape, which I did not touch the middle seam on(where the top and bottom meshes meet at the waist), and the Muse shape. The red line marks the placement of the navel on a normal shape and continues over the Muse shape to show what it does to skins. Keep in mind, the same skin is being used on both shapes.
Some people don't mind how the stomach looks on Muse, but a lot of people do. It's fine if you want to preview on Muse in ADDITION to another shape but I strongly recommend primarily using a normal shape (basically anything but Muse/Rump, haven't come across any others that warp the stomach like this) to preview your skins on.

But anyway, back to the rest of the tips..

1. SEAMS!!! GET RID OF THEM! Use the wireframe included in the skin templates you (hopefully) got from IMVU, and not purchased from another source.. (Sorry, but I am really against that. I am all for devs doing their own work though!). Anyway, if you use the wireframe map that should be the top layer in the template, you will see where all of the seams and where they line up. Try your best to match them up, don't just do random shading everywhere because you WILL end up with tons of seams, they just might not be so obvious without the right pose.
2. Don't be afraid to USE the previewer. By that, I mean don't be afraid to make only a single edit, and preview it a hundred times before being finished with that particular area of the body. Personally, I must save and hit Apply Changes about 5,000 times before submitting a skin. Don't feel like you need to work on the skin until it's done and THEN preview it and fix 2 things before submitting, inspect hard to find areas! It is a Previewer for a reason.
3. I just recently found this page by Keef with a simply AMAZING tool for skinners. Basically, you derive from that product, and you will have the main avatar in the middle where you can load other products onto it(including heads..etc..), and then two dummy avatars on the sides. One has the neck from the body(located between the legs on the map), and one has it from the neck on the head template, and with her eyes closed so you can see the makeup from that position. One is posed normally and the other has her arms and legs spread out so you can see where seams are and fix them. You'll have to look through the maps to find the ones for the skins, they are both titled m02 and m07 like on the regular skin file you derive from, but there might be multiples(I don't remember). When your skins are done, you do NOT submit that derived product(unless you want your customers to have two dummy avatars next to them!). You close it out and derive from the regular skin file(252 for females) like you would normally.
4. DO try your skins on different heads! Skins don't look the same on every head. Some heads lips are larger and others smaller, and some use more space of the template than others. Not to say that you need to optimize your skins for every single head out there, because that's impossible, but frequent the Heads part of the catalog and check out the Hottest Products. See what the most popular ones are, and try to work around those. Also on the page I linked above, there are new wireframe maps for the head files, that has the area outlined for both the lips on the default heads and lips on other heads. That way, you can ensure both lip areas are covered completely with your lip color of choice and nothing looks awkward with skin-colored spots.
5. I also encourage you to preview your skin with the wireframe layer visible(even at 5% opacity) once in a while, to find seams and where they line up, because let's face it. The avatar template here on IMVU is horrible. What works for me if I am looking for where a specific part of the avatar template lines up with another part, I'll make a new layer and draw two big bright red/blue/whatever color that doesn't blend with your skin tone, right onto those areas where I think they meet. Then I can preview it and adjust until I know where they are, and I can do what I want to do.
6. Don't ignore parts of the body you don't think people will pay much attention to(such as the hands, feet and ears). Change up the ears, don't leave the same IMVU template one every time. It's nice to see something different. The same goes for the hands and feet. Add knuckles, nicer looking ankles, visible Achilles tendons(will require matching a seam up on the leg.. huge pain in the ass)..etc.. Add some detail to the bottoms of the feet(I am currently working on that too). Don't leave it looking like she walked in mud.
7. Don't just make minor edits to the default template and think you'll be safe from seams because it was made by IMVU, because unfortunately, you are wrong. Even the default ugly MCG skin by IMVU has seams, so pay attention to where they are so you can fix them.
8. Don't be afraid to photosource. However, please bare in mind that there IS A DIFFERENCE between Photosourcing and screenshot sourcing. I know most of you know better than that, but for those who don't, please don't steal other people's work. Whether it's from IMVU, the Sims, Second Life, or another virtual community. These designers work hard on their skins and would not like their work being stolen and climed as someone else's. There are enough people on this website that are on other communities as well that would recognize them from a mile away. I know I do, so please do your own work, and beware of file sellers that may or may not be original creators. That is the risk you run when you use others work. For photo sourcing, don't feel like IMVU is too crappy to handle it, lol because surprisingly it isn't. I photosource at least 10-15% of the parts of my skins, and then edit them a ton. The trick is for it to not be obvious you photo sourced. Make sure the quality of the photosourced areas of your skin match the quality of the hand-drawn areas. Don't have a super smooth, minimally detailed body and then have a really elaborately detailed stomach that far surpasses the rest of the skin. Try to even it out a bit. Add details elsewhere too, don't JUST focus on the upper torso. Pay the legs and arms some attention.
9. The one thing that bothers me a lot about IMVU skins is that they all kind of tend to look the same in the end(even before file sales were the new thing to do). If you think about it, so many IMVU skins stomachs just have the same basic "U" shape to them. Try for some more blending along the sides of the avatar, below her ribs, and make the stomach look like it's actually part of the skin, rather than drawn onto it.
10. Know which parts of the avatar template stretch, and how. Below I've written a helpful list of every part of the avatar that I know to stretch, and which way. Keep in mind, that the way I've written them is the way they stretch ON THE FLAT TEMPLATE. So if I say horizontal, it will be horizontally on the template, even if that part of the body is vertical on the actual avatar.
Arms: horizontally stretched(you need to squish things horizontally that you do on the arms).
Rib area, below armpits to hips: Squished horizontally. Anything you do will need to be STRETCHED horizontally to look right in this area.
Upper back: This area STRETCHES horizontally. You will need to squish anything you do here.
Legs: Slightly squish a bit. You will need to SLIGHTLY stretch the knees and back of the knees horizontally here. Only by a little bit, but the distortion is there and there are so many squished knees.
11. Don't be afraid to do pixel work on either template. The templates stretch and blur considerably on every area in some way, and it will be blurred on the template anyway. You won't end up with boxy pixel stuff, so instead of using a 1px brush, try using a 1px pencil instead. It will clean up what you're doing, and give room for more precision. The nose on the face template is a great place to practice this.
12. When doing pushup cleavage(smooshed together, not separated), don't ever use a straight line. It should be basically a backwards C next to a regular C. Not a flat bottom with a super straight line up the front. If you do decide to go with that anyway, you should add more shading and blur at the top of and around the cleavage line. I've seen one particular skin around lately(no idea who it's by), where the cleavage looks almost like origami of some sort, the way it's a straight line and minimal shading around it. It looks like it has corners, which it shouldn't. Boobs are round, not square! Lol

Edit: 13. Be careful of your layer blending modes! I thought I added this before but I don't think I did. Anyway, I'm not sure how many of you actually do your shading and highlighting in separate layers, I know a lot of you just use dodge and burn. But I like to do separate layers for mine, so I can adjust them as I need and not ruin the rest of the skin. My point with this being, if you do use separate layers, here is my suggestion: Use the same color as the base of the skin for both. Your shade and highlight will come with layer blending modes(normal, multiply, screen...etc.). When setting your layer to multiply, you will need to desaturate the layer by about 30-50 points, depending on the color of the skin. Multiply increases the contrast, which in turn increases the saturation and gives it that orangy look. If you desaturate it a bit, it will keep the natural tone. And of course, adjust your opacity so it blends well instead of looking like a giant hard shadow. For screen, this one is tricky. You will need to adjust the hue by about -20(at least.. this is to make it more pinkish), because for whatever reason, screen tends to make things look peachy/orangy. You will also need to jack up the saturation a bit, but not too much(set your layer to screen and THEN make your adjustments). And of course, your opacity as well.
Here's an example of what I mean for each:
You can definitely tell the difference from the left to the right. The right one was with the saturation and hue adjustments for the multiply and screened layers(both using the same color as the ball without shading or highlights). The left is just plain multiply and screen, with no adjustments. The one on the right with the adjustments looks much more natural than the one on the left, which looks a bit over-saturated and orangy.

For tattoos!
I said this in old help indexes of mine, and then people started relaying the info as their own, so you probably already know it by now but I will say it once more in case you don't!
NEVER EVER EVER leave your tattoo layers at 100% opacity. I always said 70% was a good opacity to use, so it is slightly faded and looks more like a tattoo rather than a sticker.
I'm adding some more to this though: Depending on the color of the skin, you should use between 40% and 80% opacity. Less opaque for super pale skins, more opaque for darker skins. Also, if it is a lot of solid black work, you need to use even less opacity. Black is a very dark powerful color when it comes to tattoos on IMVU and they can be ruined very easily by being too dark on a light colored skin.
If the tattoo you're using has a ton of detail on a white or supposed-to-be-white background, set the blending mode to multiply and it will get rid of the white but keep the detail of the tattoo. If you still have a dark box around your tattoo layer, hike up the brightness and contrast until it is gone.

Edit: Also adding, PLEASE USE THE DEFRINGE TOOL! If you are sourcing a tattoo and instead of using multiply for the blending mode, you're cutting out the white background, please get rid of the white matte dots that border the tattoo. To do this, (in photoshop) go to Layer>Matting(located at the very bottom of the drop-down menu)>Defringe. Set it to 1 and click OK. When you use larger sized templates you will need to set it to 2 or 3, but for how small the IMVU templates are, 1 is optimal.

[22/7/2010] Edit2: Really utilize the previewer and template. By that I mean, really understand that you are working on a flat image that is manipulated, warped and stretched around a 3d object. Understand that just because something looks great on your flat image, it may not look so great on the template due to an uneven surface. Like I said above, don't be afraid to preview your skin with the wireframe map visible(at 5-10% opacity). It's there to show you where everything ends up once it's on the avatar mesh. Don't be afraid to look at the wireframe in on the 3d avatar and sort of "map out" where you want to put things. Take a screen shot, put a dot where you want something, find that spot on your template using the wireframe map for reference and work on it. Something might look totally weird or like crap on the template but then look great in the previewer. Don't be afraid to do something weird on your template, because it's not the template that matters it's how it looks on the avatar in the previewer. It's hard to stress how much this matters because I think most people won't bother previewing something that looks awkward on the template. Like, I think most people don't REALLY understand angles and different view points on a flat image as opposed to a 3d object. People are used to a flat image having one viewpoint: straight. And if it doesn't look good from that viewpoint, it doesn't look good at all and you really need to erase that mentality! I think people tend to draw something on the template to look exactly how they want it to look on the avatar from a front viewpoint, but get frustrated when it doesn't look the same in 3d. You need to draw it from all angles at once, if that makes any sense at all. I can't really think of any good examples that would be easy to understand, but if I do I'll post one. xD But basically remember that it's an image being wrapped around something. Remember that you might have to obscure your shading for it to end up in the right spot on the avatar instead of drawing it in relation to a specific viewpoint. Okay that's also a bit confusing but yeah.. Maybe some of you get what I mean?

I know this was long, but I hope that I helped anyone who may have had questions about these issues. If you have any more questions, or any comments please feel free to reply here or message me._________________

Last edited by Scarling on Sun Jul 24, 2011 4:17 pm; edited 7 times in total

And I just added a new one at the bottom, plus an image with an example. I thought I already mentioned it somewhere in the tips but I didn't see it anywhere, so I added it just now. I included an example image to show the difference between not adjusting the layers, and adjusting them. _________________

I hope this thread is still alive. I have a mayor issue with collarbone and seams in this area, I've done just about everything mentioned in this tutorial trying to figure out what the problem is, but I can't come up with the solution.

Samples: (please disregard the enhancement itself, this is just a quick sample of where the funky seams show)

Is there a way to avoid these, I've seen perfectly seamless collarbones in the catty as well as on your skins.

Bump because I added a new one to the list at the top. Hope it's helpful

@Caribbean: Sorry for taking so long to respond, I hadn't checked up on the thread in ages. If you're still here and read this, the neck part of the map is located between the legs on the body template. It's that weird band-aid shape. The curved part is where it attaches to the neck where the collar bone seam needs to be lined up. The straight parts wrap around and meet on the back of the neck. What usually works for me is drawing the collar bone all on the torso, and then cutting around the seam and pasting/rescaling it to the neck part between the legs. Also to help line it up correctly I temporarily set the layer to multiply, just to see the edges better (make sure to use the wireframe layer to see the seams for this, as it won't be accurate otherwise)._________________

Hey, I hope you still occasionally check this thread because I need some help with a seam that keeps bugging me in my skins (usually I give up and just keep that area one color). I create/design furs and for some reason I can't get rid of these weird "perpendicular symbol" (sorry not sure how else to describe it lol) parts of skin that stay the background color, making black stand out in the middle/backs of her shoulders in the midst of white x.x
It looks horrid and I'm hoping you can help me solve this >.<;

Hey, I hope you still occasionally check this thread because I need some help with a seam that keeps bugging me in my skins (usually I give up and just keep that area one color). I create/design furs and for some reason I can't get rid of these weird "perpendicular symbol" (sorry not sure how else to describe it lol) parts of skin that stay the background color, making black stand out in the middle/backs of her shoulders in the midst of white x.x
It looks horrid and I'm hoping you can help me solve this >.<;

Can you post a picture so I can see exactly what you mean? I'm having trouble getting a visual._________________

Hi! :3 I'm really glad you pointed out something on the Mirai shape versus the Muse/Rump shape. Can I ask where you find the Mirai shape though? Or the normal body shape? ^^

The Mirai shape is mine and can be found in my catalog(just click the derivations link and find a bikini made on it). But I don't think any shapes really distort the stomach like the muse/rump shapes do. I think it was just because they altered the seam for a different look so any other shape really would work fine. Muse is cute (personally too thin for my taste though) but I just don't think it's ideal for previewing skins on because of the distortions ;o_________________